Spring loaded action contact



Och 28, 1952 c. w. KLos'rl-:RMANN 2,615,951

SPRING LOADED ACTION CONTACT Filed. May 12, 195,0 .k'gf

@WQ/M Patented Oct. 28, 1952 SPRING LOADED ACTION CONTACT Curt W. Klostermann, Chicago, Ill., assignor to American Phenolic Corporation, Chicago, Ill.,

a corporation of Illinois Application May 12, 1950, Serial No. 161,648

4 Claims.

The present invention relates to electrical connectors and has particular reference to a novel pair of electrical contact elements of an improved type, which may be referred to as spring loaded action contacts, since they exert a spring action that holds their engaging surfaces in intimate electrical union with each other and at the same time permits considerable relative movement, either in rotary or longitudinal shifting, or in angular shifting into and out of alignment. As will appear, these contacts may be used in either of two Ways. That is, they may be used with one of the Contact elements mounted on the male element of a connector and the coacting contact carried by the female element thereof, or both of the contact elements may be carried in one half of the connector to provide a spring urged contact button thereon adapted to engage a mating contact on the other connector half.

It is the primary object of the present invention to provide a pair of electrical contacts so designed that the engaging surfaces of one contact are spring biased laterally to press against a tapered surface on the other contact, so that they exert a cam action tending to urge the contact elements apart from each other, but are held in rm electrical engagement under all conditions. According to the present teachings, this spring action is attained without the use of any conventional coil or leaf springs, for example, and is in fact attained by the inherent characteristics of the two contacts, each of which comprise only a single integral unitary piece of metal.

It is a further object of the invention to provide a pair of spring urged action contacts according to this teaching, wherein the individual contact elements are spring urged with respect to each other within predetermined limits, and are provided with a positive limiting stop or abutment to prevent the contacts from being distorted as a result of forcing beyond their predetermined cperating limits.

A still further object of the invention is to provide a pair of integral and unitary spring urged contact elements wherein the contacts are maintained in intimate low resistance electrical contact at all times, even under conditions of severe axial misalignment.

A still further object is to provide a pair of improved electrical contact elements wherein the required spring effects and wiping action of the contact surfaces is attained by an unusually simple, compact and economically desirable structure including only two pieces, each of which is of simple, rugged construction, and well adapted to mass production manufacturing methods and easy assembly procedures.

The foregoing objects are accomplished in this teaching by a pair of coacting contact elements as illustrated in the drawings hereof, wherein:

Figure l is an elevational View, partly in section, showing an electrical connector utilizing a pair of the contacts of this invention to provide resiliently mounted spring urged contact buttons on its mating face;

Figure 2 is an elevational view, partly in secti-on, showing an electrical connector wherein the contacts of the present invention are employed in the opposite halves of the connector, so that they engage and disengage with each other as the connector is coupled or uncoupled;

Figure 3 is a cross sectional view of a pair of contacts according to the present teaching;

Figure 4 is a cross sectional view similar to Figure 3, but showing the contact elements positioned at the limit of relative movement of said contacts;

Figure 5 is a detail transverse sectional view taken on the plane of the line 5 5 of Figure 3; and

'Figure 6 is a detail transverse cross sectional view taken on the plane of the line I-S of Figure 4.

In Figure 1 the contact elements of the present teaching are housed within a male connector I0 which, as shown, includes a m-ounting flange II and lugs I2 arranged to coact with a mating connector. The shell encloses dielectric inserts I3 and I4, and a rubber sealing disc |15 is provided at the open end of the fitting. The inserts I3 and I4 are secured in position by a locking ring I6. The insert I3 carries the female contact element which, as shown, includes a ange mounting shank 2I having a soldering terminal 22 at the rearward end thereof and having a hollow sleeve portion 23 slotted at 24 to provide a plurality of spaced apart spring tines 25. As seen in Figure 3, the sleeve porti-on 23 is a relatively thin wall structure which is preferably formed by drilling the internal bore 26 somewhat less than the diameter of the sleeve and then bending each of the tines 25 inwardly to impart sufficient permanent set in the tines, as shown. Thus the sleeve is of somewhat tapered construction, and of lesser diameter at its outer end than it is at its base; that is, adjacent the mounting shank 2I. l

The male contact element comprises a mounting shank 3l and a conical head portion 32, with an enlarged shoulder or abutment 33 at the base of the conical portion to serve as a limit stop, as will appear. The mounting shank 3l extends through a bore 34 in the insert I4, so that the contact is free to move longitudinally in the insert, 'and the outer end of the shank has a reduced neck portion 35 which extends through the rubber seal l5 and terminates in a convexly rounded contact button 36.

The action of these contact elements will be most easily observed by examination of Figures 3 to 6, wherein it will be seen that in the normal relationship of the contacts, as exemplified by Figure 3, the inner arcuate surfaces 4'l of the tines (which are flared outwardly at their forward contacting edge) engage and bear in Wardly against the exterior arcuate surfaces 42 of the contact head 32, so that these parts bear against each other with a firm yet resilient physical engagement, which is, however, sufficient to establish an intimate low resistance electrical contact between them. It will be observed, of course, that the inward force of the tines acting on the tapered head of the male contact will exert a camming action tending toA push the contacts apart. This is utilized in the form of the invention illustrated in Figure 1, so that the spring ten-sion exerted by the tines on the male element of the contact presses it resiliently outwardly, so that when it engages a mating contact button and is moved back thereby, it merely spreads the tines 25v slightly until the parts reach a position of adjustment corresponding to the amount of inward thrust imposed on the rounded contact button 3S. Thus, as the connector is coupled and uncoupled, the male contact element shifts back and forth to effect' a wiping action between the forward edges of the individual tines, and the' outer conical surfaces of the contact head- It is tobe noted, however, that in manufacturing the female contact elements, the internal bore 26 is drilled to a diameter equal to the base diameter of the conical head 32 of the male contact, sov that the effective' internal radi-us on the inside of the tines at the contact point di is' at least equa-l tothe ra-dius of the frusto-conical portion 32 at its base, and somewhat exceeds the radius of this tapered portion at any point spaced outwardly from the base. The result is that the wiping movement between the parts can be effected without an-y tendency to scratch or gall the? smooth conical-surface ofk the malel contact head, since until the contacts rea-ch the extreme limit of their movement, the corners fil of the tines are held. in slighty but positive spacing with respect to the walls of the head (Figure 5') It has been foundy preferable to form the head portion 32 with its walls' disposed at an' angle of fty degrees with respect to each other, and it has been learned that excellent spring action is achieved withmating, contact elements according to the'proportion shown in the'drawings when thev female element is formed of beryllium copper or -me-tal'of. similar spring characteristics. rlhe male contact element may be of brass, and in actual practice itis advisable to silver plate both of the elements toY avoid corrosion. and improve the eiciency of the engaging surfaces.

It has been previously stated thatit is one of the objects of the invention to provide means for giving a longitudinal spring. action to theY contacts, yet so arranged as to prevent the spring from being distorted or permanently set by the application of' excessive force.. The manner in which this is accomplishedA according to the present teaching is illustrated in Figures 4 and 6, from which it will be seen that when the male contact element is forced sufficiently to spread the tines into parallelism with each other (that is, to return the tines to the original position which they had before being set to the requisite taper), the ends of the tines will come into straight abutment with the shoulder 33 so that this shoulder acts as a positive limit stop preventing further outward flexing of the spring tines. This provides an adequate safeguard against any accidental distortion due to overflexing. The inside radius of each of the tines is now substantially equal to the outside radius of the tapered head1 (Figure 6), so that each tine is in contact with the head throughout the entire width of its engaging surface.

The manner in which contacts of the present invention may be employed as the opposite mating elements in a separable connector is illustrated in Figure 2, wherein the female element of the contact is carried in the connector shell 5iand mounted therein by dielectric inserts-52 and 53 secured in position by the locking ring 54. With this arrangement the male Contact is provided with a terminal or soldering pocket 55 rather than the convex button head' 35, and the shank 56 of the contact isv mounted in the insert 57, which is secured inf the shell 58 by conventional locking ring 59. Thus, when the twohalvesof the connector are coupled together by the threaded ring EE, the contacts engage as shown, and the longitudinal spring action inherent in the structures compensates for any dimensional variations in the connector ttings and mai-ntains the two contact elements in intimate electrical union irrespective of deviations as to perfection in alignment and spacing between the several' parts of the assembly.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Pa-tent is:

l. In an electrical connector, in combination, a pair of coacting contact elements'longitudinally shiftable with respect to each other, one of said elements comprising a mounting shank havingl aconical head with an abutment at itsbase, the' other contact consisting of a mounting shankv having an-integral hollow sleeve with a central bore therein, withtheI wall surfaces of said sleeve split to provide a plurality of straight'spring tines of arcuateY cross section throughout their length and integral with, the sleeve and mounting shank.; said tines tapering inwardly from the mounting shank toward the conical head of the other 'contact element, with the extreme ends of the tines engaging. the tapered surfaces of theI conical head of said other contact element and exertingy a radial: spring tension iitovardly'thereonl and producing a` cam action urging said contact elements away from each other; with a housing surrounding said pair of Contact elements and includingA opposed abutment's limiting the relative movement thereof, and with one end of at least one of said contacts extending through an aperture* in the' housing and carrying a contact button projecting from the housing and shifta'ble with respect thereto.

2. In an electricalconnector, in combination, a pair of coact'ing contact elements longitudinally'VA shiftable with vrespect to each other, one* of said elements comprising a mounting shank having a` conical head with an abutment at its base, the other contact consisting of amounting shank having an integral hollow sleeve with' a" central bore therein, with the wall surfaces of said sleeve split to provide a plurality of straight spring tines of arcuate cross section throughout their length and integral with the sleeve and mounting shank; said tines tapering inwardly from the mounting shank toward the conical head of the other contact element, with the extreme ends of the tines engaging the tapered surfaces of the conical head of said other contact element and exerting a radial spring tension inwardly thereon and producing a cam action urging said contact elements away from each other.

3. In an electrical connector, in combination, a pair of coacting contact elements longitudinally shiftable with respect to each other, one of said elements comprising a mounting shank having a conical head, the other contact consisting of a mounting shank having an integral hollow sleeve with a central bore therein, with the wall surfaces of said sleeve split to provide a plurality of straight spring tines of arcuate cross section throughout their length and integral with the sleeve and mounting shank; said tines tapering inwardly from the mounting shank toward the conical head of the other contact element, with the extreme ends of the tines engaging the tapered surfaces of the conical head of said other contact element and exerting a radial spring tension inwardly thereon and producing a cam action urging said contact elements away from each other, with a housing surrounding said pair of contact elements and including opposed abutments limiting the relative movement thereof,

and with one end of at least one of said contacts extending through an aperture in the housing and carrying a contact button projecting from the housing and shiftable with respect thereto.

4. In an electrical connector, in combination, a pair of coacting contact elements longitudinally shiftable with respect to each other, one of said elements comprising a mounting shank having a conical head, the other contact consisting of a mounting shank having an integral hollow sleeve with a central bore therein, with the wall surfaces of said sleeve split to provide a plurality of straight spring tines of arcuate cross section throughout their length and integral with the sleeve and mounting shank; said tines tapering inwardly from the mounting shank toward the conical head of the other contact elements, with the extreme ends of the tines engaging the tapered surfaces of the conical head of said other contact element and exerting a radial spring tension inwardly thereon and producing a cam action urging said contact elements away from each other.

CURT W. KLOSTERMANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 896,210 James Aug. 18, 1908 2,415,404 Baller Feb. 11, 1947 2,487,098 Carington et al Nov. 8, 1949 

